The news is released and confirmed by MuscleNerd through his Twitter account which says:
“MuscleNerd recently tweeted, Got “backup plan” for untethered 4.2.1 JB working (video coming up). Uses mysterious 4.2b3 hashes Cydia kept for you.”(It’s a “backup plan” because comex is working on a more extensible one, but this method is also generalizable)

iPhone Dev Team has also released a teaser video of untethered iOS 4.2.1 jailbreak. Check the video to see the action.

Stay connected to VeryRite as we will be covering everything regarding the upcoming untetehered jailbreak of iOS 4.2.1. We are waiting for more updates to distribute it to our visitors.